Butomus umbellatus is not yet a widespread plant in Wisconsin,
but it appears to have the potential to be a serious invasive species.
It grows in marshes and can tolerate water as deep or deeper than that
in which cattail is normally found (up to 2 meters), extending to the
deepest range of our emergent marsh species, except possibly for hard-stem
bulrush and wild rice. Once established in a marsh, populations increase
and persist indefinitely. The good news is that it has spread very slowly
from infested sites to other wetlands, and may be controlled if it is
observed and destroyed within a few years of establishment.